EXECUTION METHOD OF BRANCH PART OR JUNCTION OF SEALED TUNNEL

PROBLEM TO BE SOLVED: To provide an execution method of a branch part or a junction of a sealed tunnel which minimizes the concurrent use of a freezing method, and which enables the construction of a branch/junction with great depths at a low cost and with safety. SOLUTION: A temporary shielding machine 2 of a smaller diameter than that of the two shield tunnels 1 is started one by one from the rear position of the branch part or from the front position of the junction of the two shield tunnels 1 within the two shield tunnels 1 toward the branch part or the junction so that the temporary shielding machine 2 covers the outer periphery of the branch part or the junction. Then the temporary shielding machine 2 is passed through the branch part or the junction, and is recovered within a shield tunnel 1 which is at the front position of the branch part or the rear position of the junction. Thus, an exterior execution 3 covering the outer periphery of the branch part or the junction is performed. COPYRIGHT: (C)2006,JPO&NCIPI